Various techniques have been developed for monitoring the behavior of an object. One type of such techniques utilizes one or more imagers (cameras) with an appropriate field(s) of view for tracking the object motion at the object location. Another type of the monitoring techniques of the kind specified utilizes proximity sensors for tracking the object's movement in the vicinity of the object.
Some known techniques are disclosed for example in U.S. Pat. No. 5,543,588 and WO07/017,848. U.S. Pat. No. 5,543,588 describes a handheld computing device which comprises a thin enclosure having two opposing major faces. A display screen is disposed on a first one of the major opposing faces of the enclosure and a touch-sensitive object position detector input device is disposed on a second one of the major opposing faces of the enclosure. Computing device circuitry, circuitry for interfacing the touch-sensitive object position detector to the computing device circuitry, and circuitry for driving the display screen are all disposed within the enclosure. WO07/017,848 describes a system for determining information regarding at least one object. The system comprises a sensor sensitive to capacitive coupling; at least one object adapted to create a capacitive coupling with the sensor when at least one signal is input to the sensor; a detector adapted to measure at least one output signal of said sensor associated with the at least one object, wherein the output signal associated with the at least one object is an object information code.